The Killing: subtiltling requires an awareness of minute cultural differences between two countries. Photograph: BBC

SPOILER ALERT: This blog is for people watching Forbrydelsen II on BBC4. Do not read on if you haven't seen episodes three and four. If you have seen further in the series, please be aware than others have not – and don't post spoilers.

The reports about the toned-down swearwords in the BBC-commissioned translation of The Killing have sparked a debate about the intricacies of subtitling foreign dramas, and not without reason. After all, this is a job that requires not just bilingualism but an awareness of minute cultural differences between two countries.

Last Saturday's third episode of the second series illustrates the difficulties translators face: it's day four of the investigation – the morning after Raben's escape from the psychiatric hospital – and Strange and Lund are getting into a car while discussing progress made overnight. CCTV cameras at a petrol station have picked up images of Raben asking for a lift across the bridge straddling the Great Belt, Strange says, adding that he believes Raben must be in Jutland or on the island of Funen by now. Seconds later, and halfway into his account of Team Ægir's time in Afghanistan, Strange interrupts himself to tell Lund that he was on a date last night – or does he?

The scene has so far lasted about 45 seconds and already non-Danish speaking viewers have missed both the geographical details of Raben's whereabouts (and what did you make of his decision to expose his face in front of the cameras before escaping across a bridge in the opposite direction – the one going east across the Danish-Swedish border?) and the implication of Strange's aftale the night before. See, while aftale could be translated as "date", it seems more likely that Strange is telling Lund that he had "plans" or a "meeting" – Strange, remember, doesn't know that Lund spotted him with a blonde in the office the previous evening – but by interpreting aftale as "date" for non-Danish speaking viewers, Strange's subsequent comments about Lund being jealous seem more flirtatious than maybe originally intended.

Does it matter? It would have, had this been a less skilled production, but as so much of the story is conveyed through subtle gestures – a raised eyebrow here, a glance there – any weaknesses in the translation are more than made up for by The Killing's atmosphere. Still, there are things Danish-speakers pick up that you might miss: the second episode in Saturday's double-bill featured another conversation-in-a-car: the one where Lund tells Strange about her Swedish ex-boyfriend. "Mr Nilsson?" Strange replies sarcastically. To most Scandinavians and other die-hard Pippi Longstocking fans, that's a clear reference to Pippi's pet monkey and illustrates the sibling-style relationship between Scandinavians, often characterised by light-hearted mocking. Other cultural references similarly lost in translation include Ryvangen, the garden of remembrance where Danish resistance fighters killed in the second world war are buried and where Anne Dragsholm is found tied to one of the three execution poles originally used by the Nazis. Does that bit of information change your perception of the circumstances of her murder? It certainly did for me. And are we meant to read something into the name Perk, the mad Danish soldier Thomsen mentions in her conversation with Lund and Strange? As Kariebookish rightly points out in a comment on the blog for this weekend's episodes, Perk could be short for "perker", a derogatory term for someone with an Asian background.

The swearwords debate made the problem seem greater than it is (and, anyway, the death of Meyer towards the end of the first season has decreased the frequency of on-screen cursing dramatically): The Killing's translators do a great job digesting colloquialisms and cultural references into easy-to-read 10-word lines. But to help them along the way, we've made a cut-out-and-keep glossary of some of the most frequently uttered on-screen phrases (and, yes, quite a few swearwords among them) to listen out for. Enjoy!